Printing-press



May 28., 1935. c. w. HARROLD V PRINTING PRESS Filed Jan. 14, 1932 Patented May 28, 1935 PATENT oFFicE 2,002,814 PRINTING-PRESS Charles W. Harrold, Cleveland, Ohio, assignor to Harris-Seybold-Botter Company, Cleveland, Ohio, a corporation of Delaware Application January 14,

16 Claims.

My invention relates more particularly to multicolor rotary off-set printing-presses embodying improvements by which thecolors on the sheets or web may be readily equalized to the length of the plates in each of the colors used in the press caused by stretching of the paper and swelling due to the moisture imparted from the dampening mechanisms.

Heretofore the practice has been to correct the unequal lengths of the print from one color to another byover-packing or under-packing the plate cylinders in the several units, since reducing the diameters of the plate-cylinders lengthens the print, while increasingthe cylinder diameter shortens the print. In either case, however, the actual print is usually slightly longer than the design on the plate so that due allowance must be made in laying out the Work. Such changes in the diameters of the plate-cylinders are also objectionable in that they disturb the proper working relation with the coacting rubber-cylinder in olf-set printing by causing a pull or slip between the surface of the two coacting cylinders vso that the design on the plate will wear olf.

The objects of my invention are, among `other things, to provide a new and improved multicolor-off-set press with the impression-cylinders in the'several printing couples ground in graduated relation to one another withvvarying diameters so that this stretchingl of the paper may be taken care of in vequalizing the length of the print to that of the plate to print the several colors inaccurate registry, since the reduction of the diameter of the impression-cylinders shortens theprint, while increasing same will lengthen the print.

According to my invention as shown in the accompanying drawing in a four-color off-set press, the impression-cylinder of the fourth and last unit is o1 standard size, while the diametersV of the remaining three impression-cylinders are progressively diminished backwardly through the press to the first unit, the` impression-cylinder in such rst unit being the `smallest in diameter. In such a lay-out the several colors will print in exact registry, and the length of the print willl 'be thatof the plates onl various plate cylinders.

',Furthermore the graduatedimpression-cylinders 50 of thev several units make it unnecessary to overpack or under-pack any of the plate-cylinders to any appreciable extent, and the desired equalization of the lengths of paper is attained. Y Y Y In the drawing, Fig. lis a diagrammatic side-1 the severalprints un the 1932, Serial No. 586,521 (Cl. lOl- 136) elevation of a multi-color rotary off-set printing press embodying my improvements centered about the varying diameters of the four impression-cylinders ground in graduated relation;

Fig. 2 is a plan view of a sheet printed with the gripper edge along the left margin and the back edges on the right margin showing an overlapped relation due to the varying lengths of the print in the different colors; and

Fig. 3 is a plan view similar to Fig. 2, but 10 showing the back edges of the prints, in several colors, in registering superposition when the four impression-cylinders are ground to varying diameters according to my improvements.

Similar letters and numerals refer to similar 15 parts throughout the several gures.

Referring to Fig. 1 showing a multi-color press embodying four printing-couples or units A, B,

C and D which are all built alike and are arranged in series, each unit comprises the plate- 20 I cylinder 4, the rubber or blanket cylinder 5, and impression-cylinder 6. Superposed on the platecylinders 4 are the usual inkers I with the dampening mechanisms 8 on'right-hand lower side of the plate-cylinders 4. The feed-rollers 9 and Ill 25 Vtake the sheet S from the roller feed-table Il, and deliver such sheet to the grippers I2 on the impression-cylinder E of the rst unit A in the usual way. The gears of the cylinders 4, 5 and yI5 in each unit rotate in unison, but the surface 30 speeds ofthe cylinders areslightly different owing to their slightly different diameters. According to my invention the cylinders 5 and 6 rotate at the same angular speed since the pitch line of their respective gears are equal, thereby 35 causing both cylinders tovrnakeonev revolution in exactly the same period' of time, but due to the different diameters of the bodies lof the cylinders, the surface of the cylinder 5 runs faster than the surface of the cylinder 6. This causes 40 a slight slip between the bodies -of these cylinders 5 and 6 which reduces the length of the print since the impression surface thatA runs slower.. than the, blanket surface reduces Ythe length of the print approximately equal to the difference in the respective circumferences of the two cylinders.

lInterposed between the several printing-couples or units A, B, C and D are three transfer cylinders. I3, I4 and I5, the gears of such transfer 50 cylindersbeing twice the diameter of the gears of the impression-cylinders 6 in the four units to drive same in the directions shown bythe arrows, but the peripheries` of these transfer cylinders do not travel exactly at the same speed, since the impression cylinders are half the diameter of Each transfer cylinder I3, I4 and l5 is provided with two sets of oppositely-disposed grippers I6 and I'I to carry the successive sheets S through the several units. The heavy line P indicates the path of the sheets through the press, and the delivery chains I8 with the grippers I9 passing around thedelivery drum 29 take the sheets S printed in fo'ur colors vfrom the impression-cylinder t of the printing-couple D to the delivery table (not shown). Since the gearing on the cylinders Il, and 6 in each unit A, B, C and D all have the same number of teeth and the gears of the transfer cylinders i3, I4 and I5 have exactly twice as many teeth, the cylinders 4, 5 and 6 make two revolutions in exactly the same time as the transfer cylinders I3, I4 and i5 are making a single revolution.

The press is driven from the motor 2l by the belt or chain- 22 passing around the pulley 23 andthrough a train of gears 24, 25 and 26 to the transfer-cylinder I4. A

According to my invention, the impressioncylinder 6 of the printing unit Dis of standard size while the diameters ofthe cylinders 6 of the units C, B and A are progressively diminished backwardly through the press to the first unit A, the impression-cylinder 6 of' which unit A having the `smallest diameter. For example, I have found that where impression-cylinder 6 of the last unit D is ground to `18 inches diameter, the desired equalization of the lengths of the prints on the sheets` S may be attained by grinding the diameter of cylinder 6 of unit C to 17.996 inches, with the diameter of cylinder 6 in unit B ground to 17.992 inches, and that of cylinder 6 in unit A ground to 17.988 inches. This difference (4/1000th of an inch) for the varying units is not essential, and these -gures are given only by way of example to show how the several impression-cylinders B may be ground in graduated relation to each other in the multi-color units to equalize the lengths of the prints on the sheets S as they receive their successive colors, because the edges of the cylinders in the several units are maintained in proper relationandbecause of the difference in speeds between the printing surfaces of the impression cylinders 6 and the surfaces of the blanket cylinders 5 as hereinbefore described.

Referring to Figs. 2 and 3 the sheet S is shown with the gripper edge on the left and the front line of the print marked L. Where the impression-cylinders 6 ofthe four units A, B, C and D are of like diameter without over-packing or under-packing the plate cylinders 4 to any ap,- preciable extent, the varying lengths of the prints in the several colors in the units yA, B, C and `D are shown in Fig. 2 and are designated respectively A', B', C' andiD', such variations being due largely to the stretching and swelling ofthe paper caused by moisture imparted "to the plate-cylinders 4 from the dampeners 8. y

Fig. 3, however, shows the sheet S with the back edges (A', B', C and D) ofthe prints 'inY several colors all in registering superposition when the impression-cylinders 6 are ground to varying diameters as hereinbefore described to embody my improvements.`

My invention4 in` its broadest aspects is no limited to the particular constructionsshown, as many changes may loe-made without 'departing from the principles of the invention embodying an improved multi-color printing press slightly less than one-1 the transfer cylinders.`-`

in which the impression cylinders are ground in graduated relation to one another so as to equalize the length of the prints of the several colors on the sheet and thereby obtain accurate registry.

I claim as my invention.:-

l. A rotary printing-press comprising a series of printing units, the impression-cylinder of each preceding unit having a smaller diameter than its contacting cylinder and the impression-cylinder in the successive unit.

2. A rotary printing-press comprising a series of printing units, the impression-cylinder of each preceding unit being of progressively smaller diameter than its respective contacting cylinder and the impression-cylinder in the successive unit. i

3. A rotary off-set printing-press comprising a series of printing umts having impression, transfer and plate cylinders, each of the impression-cylinders having a different diameter relatively to the others.

4. A rotaryprinting-press comprising a series of printing units having impression-cylinders, each of said cylinders having a diierent diameter and its impression surface travelling at a speed diiferent from the others.

5. A rotary printing-press comprising a series of printing units having impression-cylinders, the diameters of said cylinders being progressively different through the press with the surface of the impression-cylinder of each preceding unit having a lesser surface speed than its coacting cylinder.

6. A rotary printing-press comprising a series of printing units having impression-cylinders, the diameters of said cylinders in each successive unit being relatively larger forwardly through the press with the surface of the impressioncylinder of each preceding unit having a lesser surface speed than its coacting cylinder.

7. A rotary printing-press comprising a series of printing units having impression-cylinders, the diameters of said cylinders in each successive unit being in equal graduated relation and progressively larger forwardly through the pressy with the surface of the impression-cylinder of each preceding unit having a lesser surface speed than its coacting cylinder.

8. A rotary printing-press comprising a series of printing units having coacting cylinders including impression-cylinders, each, of said impression-cylinders having a different diameter and the respective impression surfaces of said cylinders travelling at different speeds. l

9. A rotary printing-press comprising a series of printing units having coacting cylinders including impression-cylinders, each of said impression-cylinders having va different diameter andthe respective impression surfaces of said cylinders travelling at diiferent speeds, and means for actuating said cylinders.

- 10. A rotary printing-press comprising a. series of i printing units havingr impression-cylinders, each of said cylinders having a different diameter but rotating at the same angular velocity.

1l. A rotary printing-press comprising a series of printing units having' coacting cylinders including an impression-cylinder, the impression-l cylinder of each preceding unit having a smaller diameter than its coacting cylinder but travelling at the same angular speed therewith.

12.` A- rotary yprinting-press comprising a series of printing units each having an impression-cylinder and a contacting cylinder so arranged that the ratios of the diameter of the impression-cylinder to the diameter of its contacting cylinder are progressively smaller in each preceding unit.

13. A rotary printing-press comprising a series of printing units each having an impressioncylinder and a contacting cylinder .so arranged that the diameter of, each preceding impression cylinderlis less than the diameter of its contacting cylinder by a progressively increasing difference.

14. A rotary printing-press comprising a series of printing units each having an impression-cylinder and a contacting cylinder so arranged that the diameter of the impression-cylinder in each unit is smaller than the diameter'of its contacting cylinder by a difference-greater than the relative differences in the succeeding units.

15. A rotary printing-press comprising a series of printing units having impression cylinders of different diameters, the respective diameters of which are relatively larger in each successive unit forwardly through the press to compensate for changes in the length of the impression-receiving material passing through the press.

16. A rotary printing-press comprising a series of printing units having impression-cylinders of different diameters, the respective diameters of which are relatively larger in each successive unit forwardly through the press whereby the ratio of the length of the printed impression to the length of the corresponding form is progressively smaller in each preceding unit.

CHARLES W. HARROLD. 

